<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8"/>
        <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
        <meta http-equiv="X-UA-Compatible" content="ie=edge"/>
        <title>Document</title>
        <script src = 'jquery-1.10.1.min.js'></script>
        <script>
            /* 
                filter   过滤 对已经获取到的网页元素进行过滤
                not  filter的反义词
                has      拥有，直接判定子节点中是否有符合条件的元素。
             */
            $(function(){
                // $("div").filter(".box").css("backgroundColor", 'orange');
               
                // $("div").not(".box").css("backgroundColor", 'orange');

                // $("div").has(".box").css("backgroundColor", 'orange');
            })
        
        </script>
    </head>
    <body>
        <div class = 'box'>div1</div>
        <div>div2 <strong class = 'box'></strong></div>
    </body>
</html>